<template>
  <div >
    <div v-for="(item,index) in arr" :key="index" style="display: inline-block">
       <input type="checkbox" v-model="usernum" :value="item">
    <span >
      {{ item}}
    </span>
    </div>
    <p>你选的元素累加的值和为:{{num}}</p>
   
  </div>
</template>

<script>
export default {
  data() {
    return {
      arr: [9, 15, 19, 25, 29, 31, 48, 57, 62, 79, 87],
      usernum:[]
    };
  },
  computed:{
    num(){
        return this.usernum.reduce((sum,obj)=>sum+=obj,0)
    }
  }
};
</script>

<style>
</style>